Secret ingredient found for better coffee quality

The University of Oregon explains how water added to beans can improve the taste of coffee.

Coffee connoisseurs have long argued that adding a small amount of water to the beans before grinding them can change their taste. New study researchers from the University of Oregon seem to confirm why this is the case.

“When you grind coffee, it goes everywhere,” said study co-author Christopher Hendon, assistant professor of computational materials chemistry at the University of Oregon.

“The dust coming out of the coffee grinder is like a trail that covers everything. But if you add a little water, it will not fly apart. This makes the coffee grinding process cleaner. That was the main reason people did it.”

The clutter is caused by static electricity, which is caused by friction as grains smash against each other. This static charge causes the ground coffee particles to repel each other – like magnets of the same polarity – and spray out in all directions.

Water acts as an insulator, weakening this effect – a process known as the “Ross drop” technique. “It was first suggested by some enthusiast on a home barista forum,” Hendon said. “The idea has been around for several years and was originally borrowed from the materials industry, such as wood pulp.”

However, what started out as a way to reduce clutter has gradually evolved into a more sophisticated way to get a better drink. The theory was that by reducing static electricity, the water not only kept the coffee grounds from scattering or sticking to the inside of the grinder, but also prevented microscopic lumps from forming during brewing.

Why are lumps bad? Because water flows around them, leaving behind untouched coffee and therefore its taste. They reduce the extraction yield, or the amount of coffee that ends up in the cup and dissolves in the liquid.

“The result is that when you push water through, you end up with less surface area in contact with the water, and therefore less coffee extracted,” the scientist says.